Horned lizards, also know as Horny Toads, represent a unique group of lizards that inhabit the southern United States and northern Mexico. The Texas Horned lizard, Phrynosoma cornutum, is perhaps the most recognizable species of Horned lizard. It is the largest North American native species of Horned lizard (Family: Phrynosomatidae) and has the widest distribution of any other Horned lizard species in the Unites States.
Once extremely common, they are now in decline throughout much of their range. The Texas Horned lizard is perhaps the most threatened member of this group, with estimated population declines of greater than 30% across its range (Texas, Oklahoma, Kansas, New Mexico, and northern Mexico) and even higher in Texas (Linam 2008, Henke 2003). Populations have disappeared in East and Central Texas, and are decreasing in North Texas as well.
Staff of the Dallas Zoo are studying the life history of Texas Horned lizards at the Rolling Plains Quail Research Ranch (RPQRR). The Rolling Plains Quail Research Ranch (RPQRR) is 4,700 acre preserve located in Fisher County, Texas. By collecting lizard life history data (including but not limited to population densities, habitat preferences, diet, sex ratios, activity patterns, etc…) we hope to shed valuable light on the ecology of this threatened native Texan.
In addition we are assisting Dr. Dean Williams (Texas Christian University) in his Texas Horned lizard genetic research. He is has been examining the population genetic structure and dispersal patterns of horned lizards in Texas and more recently looking at possible fine scale sex-biased dispersal patterns.
